Crayfish stocks collapsed in Turkey in mid 1980’s due to crayfish plague epidemics, with up to 25% survival in some cases. The collapsed stocks have then recovered slowly and commercial crayfish fishery was reinitiated gradually within a decade. We examined the prevalence of Aphanomyces astaciDNA in the narrow clawed crayfish (Astacus leptodactylus) collected from two Turkish lakes, Lake İznik ...

The anti-predator behaviours of a New Zealand freshwater crayfish (Paranephrops zealandicus) to the native long-finned eel (Anguilla dieffenbachii) and the introduced brown trout (Salmo trutta) were investigated. Crayfish modified their behaviour in the presence of both trout and eels. However, a significantly greater number of defensive chela displays and swimming responses were made to eels t...

(Orconectes virilis) Mae Kindler and Jenna McCullough University of Minnesota – Itasca Biological Station Animal Behavior – June 29, 2010 Abstract Territoriality in female northern crayfish, Orconectes virilis, was studied through the observation of resident-intruder crayfish pair interactions based on size asymmetry. Resident-intruder pairings were chosen among 18 crayfish, with a total of 51 ...

Crayfish are charismatic creatures of high interest to humans, among others playing key roles in freshwater ecosystems. Considering the significance of indigenous crayfish species (ICS) as well as the risks posed by non-indigenous crayfish species (NICS) that may dissemite a crayfish plague pathogen Aphanomyces astaci, astacological research has advanced particularly in Europe. In this context,...

Signal Crayfish (Pacifastacus leniusculus) are thought to be a species of commercial production potential, however there are a number of culture techniques that need to be better refined before commercial production is viable in Canada. This project sought to establish culture techniques for the species, by assessing growth and survival of juveniles as well as the digestive capabilities of adul...

The spreading of new crayfish species poses a serious risk for freshwater ecosystems; because they are omnivores they influence more than one level in the trophic chain and they represent a significant part of the benthic biomass. Both the environmental change through global warming and the expansion of the pet trade increase the possibilities of their spreading. We investigated the potential o...

Two silver-contaminated diets were prepared by exposing juvenile rainbow trout for 8 d to waterborne silver thiosulfate as Ag at either 0.1 microg/L (low-Ag diet) or 80 mg/L (high-Ag diet). The level of total Ag accumulated in whole low-Ag fish was below the detection limit of analysis. Whole high-Ag fish accumulated Ag at 21.3 nmol/g. The livers of the low- and high-Ag fish accumulated Ag at 0...

The red swamp crayfish (Procambarus clarkii) has been widely introduced into aquatic systems all around the world, triggering multiple impacts. In Doñana Natural Area, Abalario and the Biological Reserve of Doñana, Spain (one of the most important biodiversity reserves in Europe), the red swamp crayfish was first introduced in 1974 and expanded its range quickly through marsh habitat, but distr...

The Louisiana red swamp crayfish, Procambarus clarkii, which was introduced into east Africa in the 1950s or 1960s, has since widely dispersed. Previous work by our group has shown that P. clarkii can reduce populations of the molluscan intermediate hosts of human schistosomes through predatory and competitive interactions. Here, we investigate whether crayfish can reduce populations of Bulinus...

Successful invasion by nonindigenous species is often attributed to high propagule pressure, yet some foreign species become widespread despite showing reduced genetic variation due to founder effects. The signal crayfish (Pacifastacus leniusculus) is one such example, where rapid spread across Japan in recent decades is believed to be the result of only three founding populations. To infer the...